Net Revenues by Geographic Area (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011		Sep. 30, 2012		Sep. 30, 2011
Segment Reporting Information [Line Items]
Net revenues	$ 136,496	[1]	$ 125,894	[1]	$ 417,201	[1]	$ 350,836	[1]
United States
Segment Reporting Information [Line Items]
Net revenues	105,173	[1]	93,925	[1]	319,269	[1]	263,047	[1]
the Netherlands
Segment Reporting Information [Line Items]
Net revenues	28,335	[1]	27,583	[1]	90,242	[1]	79,734	[1]
Other international
Segment Reporting Information [Line Items]
Net revenues	$ 2,988	[1]	$ 4,386	[1]	$ 7,690	[1]	$ 8,055	[1]

[1] Net Revenues are attributed to countries based on location of where revenue is recognized.